This application claims the priority of German patent 198 32 384.0, filed Jul. 18, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an independent wheel suspension in a semi-trailing, trailing or compound arm construction having a wheel suspending semi-trailing, trailing or compound arm which is disposed at at least two points on the vehicle body and which has a wheel carrier which can be swivelled approximately about a vertical axis, the swivelling axis of the wheel carrier being situated behind the wheel axle with respect to the driving direction, whereas the wheel carrier in front of the wheel axle is elastically supported in the transverse direction of the vehicle on the semi-trailing, trailing or compound arm.
An independent wheel suspension of this type is known from German Patent Document DE-OS 21 58 931 (corresponding to GB 1 345 859). During cornering, the wheel carrier changes its position relative to the semi-trailing arm. On the wheel which is on the outside during the cornering, the wheel carrier swivels against the semi-trailing arm, in which case the wheel assumes the toe-in position. As the result of the relatively rigid bearing between the semi-trailing arm and the wheel carrier, the semi-trailing arm bearing must be elastically disposed with respect to the vehicle body. During cornering, the flexibility of the semi-trailing arm bearing reduces the positive toe-in change because of the special wheel carrier bearing.
The invention is based on the problem of providing an independent wheel suspension in the semi-trailing or compound arm construction which has a lateral-force-oversteering effect while the longitudinal suspension comfort is high.
The problem is solved by independent suspension for a vehicle wheel, comprising: a wheel suspending arm disposed on the vehicle; a wheel carrier elastically supported in a transverse vehicle direction on the wheel suspending arm via an elastic joint located forward of an axle of the vehicle wheel relative to a vehicle forward driving direction, said wheel carrier being swivellable about a wheel-carrier swivelling axis which is at least approximately vertical, which is located proximate a center plane of the vehicle wheel, and which is located behind the axle relative to the vehicle forward driving direction; and a swing arm arranged behind the wheel axle, said swing arm being coupled to said wheel carrier at said wheel-carrier swivelling axis, said swing arm being coupled to said wheel suspending arm at an arm-side swivelling axis which is at least approximately vertical, and which is located proximate an inner rim flange of the vehicle wheel.
According to the invention, a swing arm, which has approximately vertical swivelling axes, is arranged between the wheel carrier and the semi-trailing arm or a compound arm in the area behind the wheel axle. In this case, viewed in the transverse direction of the vehicle, the wheel-carrier-side swivelling axis of the swing arm is situated in the proximity of the wheel center plane, while the semi-trailing-arm-side swivelling axis of the swing arm is situated in the area of the wheel-interior rim flange.
A rim space area is defined as the proximity of the wheel center plane which is halved by the wheel center plane and has a depth of half the rim width. The area of the wheel-interior rim flange is a zone which extends from the rim flange plane of the interior rim flange in each case by a quarter of the rim width into the rim space and out of the rim space.
The wheel carrier is not rigidly arranged on the semi-trailing arm but, on the one hand, is disposed by way of a swing arm aligned approximately transversely to the driving direction in the construction of a four-point arm and, on the other hand, is disposed in a sliding joint with an elastic intermediate layer. The wheel carrier, which, with respect to the transmission, is uncoupled from the semi-trailing arm, together with the swing arm, forms a type of slider crank, in the case of which the swing arm is the crank while the wheel carrier represents the slide member.
During all acceleration operations, the crank, thus the swing arm, swings by several angular degrees about a neutral position. The wheel suspension, which is relatively soft in the longitudinal direction of the vehicle, has a high longitudinal suspension comfort. During a swinging motion caused by braking, the wheel changes into a stabilizing toe-in. During cornering manevers, the independent wheel suspension has a lateral-force-understeering effect since, because of the elastic flexibility of the slide joint, the wheel steers into the turn.
The special type of the bearing of the wheel carrier on the wheel-suspending semi-trailing arm can also be used in the case of different axle types, for example, in the case of a compound arm axle. In the case of this axle type, the respective trailing arm takes over the bearing of the wheel carrier.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.